1. Field of the Invention
This invention relates to apparatus for disassembling electrical circuitry and, in particular, to a tool for extracting an integrated circuit package from a circuit board.
2. Description of the Prior Art
A number of integrated circuit extraction tools, such as those disclosed in U.S. Pat. No. 3,797,092 issued to N. S. Einarson on Mar. 19, 1974, U.S. Pat. No. 3,602,971 issued to W. M. Halstead on Sept. 7, 1971 and U.S. Pat. No. 3,757,406 issued to W. Bezar on Sept. 11, 1973, have a generally plier-like appearance with the clamping ends having a number of slots for engaging the pins along the sidewalls of the integrated circuit package. Other extractors, such as that disclosed in U.S. Pat. No. 3,896,533 issued to R. Ullman et al. on July 29, 1975, have clamping ends which grasp the circuit package at its two end faces. Either of these general types of extractors tend to be somewhat large and cumbersome so that gaining access to an individual circuit package on a densely populated circuit board is extremely difficult if not impossible. For example, in circuits wherein the integrated circuit packages are mounted in a linear, end-to-end arrangement, the end grasping tools are virtually useless since access cannot be gained to at least one and perhaps both end faces.
Another type of extractor, such as that disclosed in U.S. Pat. No. 3,640,519 issued to W. M. Halstead on Feb. 8, 1972, has an alligator-type clip configuration for engaging a plurality of the pins along the sidewalls of the package. While this type of extractor is somewhat smaller in size than the above-described types, sufficient space must be available along the sidewalls between packages to permit the opening of the clip jaws to engage the pins of the integrated circuit.
It should be noted also that in all of the extractors referred to above, the direction of the extraction force is wholly dependent upon the user. That is, if the user is unsteady, it is quite possible that the extraction force will be applied at an angle rather than perpendicularly. Should this occur, misalignment or possibly even irreparable damage to the integrated circuit pins may result.
A further limitation in the prior art extractors is that the removal of a circuit while electrical power is applied thereto is extremely risky. For instance, any misstep in the grasping of an individual package on a relatively well-populated circuit board -- should the grasping in fact be achievable -- could result in a short circuit to one or more of the surrounding circuit packages. Consequently, power must be removed from the board in order to safely effect the extraction of a circuit package.
Accordingly, it is one object of the present invention to effect the individual extraction of an integrated circuit package from a densely populated circuit board.
Another object is to configure an integrated circuit extraction tool which controls the direction of the extraction force despite any misdirection in the force applied by the user.
A further object of the present invention is to provide an extraction tool which may be advantageously used while electrical power is applied to the circuit board.